Cutting devices



y 1956 D. w. MOLlNS 2,752,741

CCCCCCCCCCCC ES y 3, 1956 D. w. MOLINS 2,752,741

CUTTING DEVICES Filed Nov. so, 1953 a Sheets-Sheet 5 //YV/Vf QWW 5, WM604 M United States Patent CUTTING DEVICES Desmond Walter Molins,Deptford, London, England, assignor to Molins Machine Company Limited,London, England, a British company Application November 30, 1953, SerialNo. 395,069

Claims priority, application Great Britain December 15, 1952 1 Claim.(Cl. 51-247) This invention concerns improvements in or relating torotary cut-off mechanisms of the kind used in cigarettemaking machines.

In a cut-off mechanism for a cigarette-making machine the cutting bladeis usually thin so as to enable the cigarette-rod to be cut cleanly.Some rigidity can be imparted to the blade by clamping it between rigidmembers, but part of the blade near theedge must be left free in orderto enable it to pass through the cigarette-rod and through the ledgerplate which supports the rod. This free part of the blade, due to itsthinness, flexes easily. An example of such a device, called hereafter arotary cutting device of the kind referred to is disclosed in UnitedStates Patent No. 1,860,197. In that example the blade is of thewell-known sickle shape and the invention described later is for usewith such blades.

Usually the blade is arranged to pass across a sharpening element oncein each revolution of the cut-off mechanism so as to keep the bladeconstantly sharp. Difficulty is sometimes experienced in sharpening theblade satisfactorily, however, because if the sharpening element isadvanced in an endeavour to grind more material from the blade edge, theincreased pressure of the element against the blade causes the latter tobend away, due to its flexibility, so that the edge does not come intoproper grinding contact with the sharpening element. In an extreme casethe blade may be bent to such an extent that its side, rather than itsedge, engages the sharpening element.

This difliculty does not often arise when the cut-off device operates onan ordinary cigarette-rod which consists wholly of tobacco enclosed in apaper wrapper. When harder or tougher materials than tobacco have to becut, however, the knife is more rapidly blunted and requires greaterpressure to resharpen it. For example when mouthpiece cigarettes arebeing made, the rod to be cut consists of double-length tobacco portionsand doublelength mouthpiece portions alternately, each of which has tobe severed to produce individual mouth-piece cigarettes. The mouthpieceportions are often made of crepe paper or other material which is harderor tougher than tobacco and which blunts the edge of the cutting blademore than does a rod consisting of wrapped tobacco only. Similarly whenmouthpiece portions are made, for example in the manner disclosed inUnited States Reissue Patent No. 20,138 by forming a continuous rod ofmouth piece material and cutting this rod into desired lengths in thesame way as cigarettes are cut from a cigarette-rod, the cutting bladetends to be blunted, due to he tough nature of the material which it isrequired to ,ut more than it would be by an ordinary cigarette-rod.

According to the present invention there is provided a rotary cuttingdevice of the kind referred to having a sickleshaped flexible bladeadapted to engage a sharpening element, during rotation of the deviceand comprising a support member which lies against the blade near theedge thereof when the blade engages the sharpening element,

2 to support the blade against bending by the said sharpening element. iI i The support member may be rotatable with the blade and as cigaretteand like rods are always in practice supported by a ledger, usually atube throughwhich the rod passes, means may be provided for moving thesupport member relatively to the blade so that the support can be movedaway from thecutti ng portion of the blade to avoid the ledger at thecutting position. For his purpose the member may be pivotally supportedon .a carrier to which the knife is attached and a cam may be suitablyarranged to cause the support member. to move atfthe appropriate times.i I

In the case of the first specification mentioned above the blade iscarried on an arm or bar pivotally connected to two shafts having axesof rotation inclined to one another. One shaft gives rotation to the armor carrier while the other gives the blade the motion of translationnecessary when moving rods are cut. In this case the support member ispivoted on the arm or carrier which is rotated by the first shaft andthe cam is fixed so that its constructional centre is coaxial with thesecond shaft.

One construction according. to the invention will be described withreference to the accompanying drawings in which:

Figure l is a perspective view of the cutting device.

Figure 2 is a side elevation of the cutting device shown in Figure 1.

Figure 3 is a view of Figure 2 looking in the direction of the arrow Abut showing only the parts more pertinent to the present invention anddrawn to a' larger scale.

Referring first to Figure 1, this shows a perspective view of a cut-offof the kind shown in the specification first mentioned. In the drawing,1 is the sickle-shaped blade which is shown hatched for clearness and isheld by a clamp 2 to a carrier 3. The carrier is pivoted to a shaft 4which constitutes the driving shaft of the cut-off and a fork, parts ofwhich are indicated at 6 is also pivoted to the carrier and joined toanother shaft which is not visible in the drawing. This other shaft isinclined at an angle to the shaft 4. As the shaft 4 rotates, the knife 1is carried round and passing through a slot in a ledger 7 cuts throughthe rod which is supported by the ledger tubes. As will be understoodfrom a study of United States Patent No. 1,860,197 the combined effectsof the two shafts and the fork 6 which constitutes part of a universaljoint causes the blade to make complete rotations and at the same timeto be translated substantially parallel to the axis of the shaft 4. Thistranslational movement is to cause the knife to move at the same speedas the rod during the time it is actually cutting through the rod.

A grinding disc 8 is mounted as shown and driven from the left-hand sideby means not shown in the drawing and is so arranged that the blade 1sweeps over it during every revolution and is thus kept sharp. As willbe apparent from the foregoing description the blade 1 is liable to bendaway from the grinder owing to its flexibility and to overcome thisthere is provided a curved plate 9, one side of which is in contact withthe blade at or near its cutting edge on the side opposite that whichengages the grinder and supports the blade against bending. As shown inFigure 3 the curvature of the plate 9 is such that it is substantiallyparallel with the blade edge. This support plate is pivoted at 10 and toits pivot is attached a cam lever 11 having a cam follower 15 at itsfree end which is not visible in Figure 1 of the drawing but which runsin a cam groove 12 formed in a plate 13. This plate is fixed to thehousing of the second shaft so that when the angle of this shaft isaltered to increase or decrease the amount of translation, the cam ismoved with it. The shape of the cam track is such that as the plate 9approaches the ledger it is caused to rotate on its pivot 10 so that itsrear end moves inward from the edge of the knife and in this way theplate passes by the ledger without contacting it.

Referring now to Figures 2 and 3 of the drawings, it will be seen thatthe cam 13 is fixed to a fixed arm 14 by which the grinding wheel 8 issupported. The above mentioned cam follower is shown in Figures 2 and 3and marked 15 while the second shaft which carries the fork 6 is marked16. The angular disposition of this shaft and thus the bladetranslational movement is altered by shifting the shaft. housing 5 in acurved block of a support bracket 17. i

What I claim as my invention and desire to secure by Letters 'Patent is:

In a cutting device for severing an axially moving rod into lengths, asickle-shaped cutting blade, a rotatable shaft, a carrier for saidblade, said carrier and blade being supported on saidshaft for rotationtherewith and for simple swinging movement about an axis transverse tothe rotational axis of said shaft, a second shaft rotatable about anaxis inclined to the rotational axis of said first shaft, said secondshaft having a portion thereof in engagement with said carrier, wherebya movement combining rotation and axial translation with respect to saidfirst shaft is imparted to said blade, a sharpening device for saidblade positioned to engage the blade during rotation of said carrier, asupport member lying against the blade near the free edge thereof whenthe blade engages the sharpening element, said support memher beingshaped to a curvature similar to that of the blade edge and lyingsubstantially parallel to the said edge, whereby the blade is supportedagainst bending by the pressure between it and the sharpening element, apivotal mounting for said support member on the blade carrier, a fixedcam, a cam follower engaging said cam and operatively connected to saidsupport member to displace the latter on its pivotal mounting toward andaway from the edge of the blade, the cam having a contour such that thesupport member is held substantially parallel to the blade edge when thelatter engages the sharpening element and is displaced on its pivotalmounting farther away from the free edge of the blade when the blade ispassing through the axially moving rod.

References Cited in the file of this patent UNITED STATES PATENTS639,677 Gilliland Dec. 19, 1899 1,846,807 Holm Feb. 23, 1932 1,860,197Molins May 24, 1932 1,893,057 Hohn Jan. 3, 1933 2,028,681 Molins Ian.21, 1936 2,035,563 Molins et a1 Mar. 31, 1936 FOREIGN PATENTS 436,663Great Britain Oct. 16, 1935 463,577 'Great' Britain Apr. 2, 1937

